The invention relates generally to rotary mowers for cutting grass, brush, and the like and, more particularly, to a mower having a central section and extension wings or end sections, each of which sections includes a plurality of cutter units wherein the cutter units on the end sections automatically disengage from the cutting units on the main section when the end sections are raised from a mowing to a transport position.
Mowers having a plurality of horizontally rotating wheels or drums on which cutter blades are mounted are well known in the art. For example, U.S. Pat. No. 4,160,356 discloses a drum mower having a plurality of vertically oriented drum units. A pneumatic tire is associated with each drum unit and the tires on adjacent drum units are in frictional engagement with each other. An external drive rotates one of the tires with the result that all of the drum units are driven to provide a horizontal cutting plane across the width of the mower.
A friction drive of the type described in U.S. Pat. No. 4,160,356 has the advantages of providing shock absorption by the individual drum units on contact with a hard or immovable obstruction. Moreover, an overload on any of the drum units will merely result in a slippage in the friction drive rather than damage to any of the drum units. The number of drum units to be joined can be varied to form a mower of selected width.
While drum mowers of substantial width can be built using the teachings of the prior art, their horizontal cutting plane limits the usefulness and serviceability of the mowers on uneven or undulating terrain. If portions of the ground being mowed are below the level of the ground supporting the mower, the grass or brush on such portions will be cut higher than desired. On the other hand, material on the portions of the ground above the level of the ground supporting the mower will either be cut too short or the cutter will be moved into contact with the ground. Additionally, servicing or repair of known drum mowers generally requires raising the mower by a hoist or the like to provide access to the cutting units.